Technical Field
This disclosure relates generally to passive optical networks, and more particularly to hardware failure protection in passive optical networks.
Background Art
Passive optical networks are data delivery networks that transmit data in high volume across optical fibers. The networks are referred to as “passive” in that they use un-powered optical splitters to facilitate data delivery to multiple clients from a single fiber. An optical network unit is a device in a passive optical network that serves multiple users. Illustrating by example, an optical network unit may serve the occupants of an office building. Each end user employs an optical network terminal to receive data from the passive optical network. Operators of passive optical networks deliver Internet access, television, and telephone services using passive optical networks configured in “fiber to the premises” and/or “fiber to the home” architectures. Passive optical networks are ideal for these applications because data delivery across these networks is fast, cost effective, and scalable.
In a passive optical network, an optical line terminal resides at one end of the network, while an end unit resides at the other. In a network operator's hardware infrastructure, an optical line terminal receives electrical signals from service providers, the Internet, etc., converts those signals to optical signals, and delivers the optical signals to end units disposed across the network. Each optical network unit then receives these signals. Packet encryption ensures that each optical network unit receives the proper data. Upstream communication to the optical line terminal is then multiplexed across the single fiber.
Hardware and software faults can occur in components within a passive optical network system. For network operators, network reliability is an issue of concern, as a single failure in the network could result in significant network downtime, frustration among customers, and a significant loss of revenue. Exacerbating this concern is the fact that troubleshooting hardware failures is complicated and time consuming. To properly determine where the failure is, a network operator may need to inspect multiple optical line terminals, optical splitters, fibers, and/or optical network units in what may be a complex optical network topology. Surviving the failures and continuing to provide service to passive optical network subscribers is desirable.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present disclosure.